1. Field of the Invention
The present invention relates to: an image forming apparatus that is capable of detecting movement of a human body to the image forming apparatus itself and changing its power supply mode on the basis of the results of its detection; a power control method to be implemented by the image forming apparatus; a recording medium storing a power control program for making a computer of the image forming apparatus implement the power control method.
2. Description of the Related Art
The following description sets forth the inventor's knowledge of related art and problems therein and should not be construed as an admission of knowledge in the prior art.
Some copiers, printers, facsimiles, and image forming apparatuses such as multifunctional digital machines that are referred to as multi-function peripherals (MFP) having copier, printer, and facsimile function, for example, are provided with a human body detecting device that detects if a person moves toward the human body detecting device itself, in order to return to normal operation mode from power saving mode and start warm-up operation.
As an example of such a human body detecting device, there has been known a human body detecting device having a piezoelectric sensor (also referred to as piezoelectric infrared sensor) that is capable of detecting a human body with less power consumption at low costs. Such a piezoelectric sensor detects a temperature change when a person moves in a detection range of the piezoelectric sensor itself.
As an example of such a human body detecting device having a piezoelectric sensor, Japanese Unexamined Patent Publication No. H06-043025 discloses a human body detecting device having a single piezoelectric sensor and a concentrator each of whose sectional detecting areas consists of different sizes of effective detecting areas. As for this human body detecting device, when a human body moves through a plurality of effective detecting areas, the piezoelectric sensor detects far infrared energy emitted by the human body and produces different output frequencies depending on the effective detecting area. The difference in the duration or the output frequency allows the human body detecting device to identify the detecting area entered by the human body.
This piezoelectric sensor detects a temperature change when a person enters a detection range of the piezoelectric sensor itself. Being installed on an image forming apparatus such as that mentioned previously, the piezoelectric sensor has difficulties in detecting a temperature change which is too small in this case: in the image forming apparatus, the piezoelectric sensor is usually directed against the direction in which a person (user) moves toward the piezoelectric sensor itself with an intention to operate the image forming apparatus. Therefore the image forming apparatus hardly identifies the direction in which a person moves toward the image forming apparatus itself or the position at which he/she pauses.
The image forming apparatus possibly may detect that a person pauses just in front of itself but hardly judges whether or not this person has an intention to operate the image forming apparatus. In order to judge whether or not he/she has an intention to operate the image forming apparatus, the image forming apparatus needs to detect whether or not any button is pressed on its operation panel or needs to detect, with an electrostatic sensor installed on its operation panel, whether or not user's hand is close to the operation panel.
Japanese Unexamined Patent Publication No. 2000-132755 discloses a technique of avoiding errors caused by unnecessary heat rays incoming in certain directions by putting a lens block (light-proof chip) in a sensor container case.
(First Object)
The human body detecting device described in Japanese Unexamined Patent Publication No. H06-043025 identifies the detecting area entered by a person but hardly identifies the direction in which this person moves unless he/she enters more than one detecting area. More specifically, if an image forming apparatus is provided with the human body detecting device described in Japanese Unexamined Patent Publication No. H06-043025, a user possibly reaches the image forming apparatus, before the human body detecting device identifies the direction in which he/she moves, only to find that he/she has to wait so long until the image forming apparatus becomes ready for operation, i.e.; until the image forming apparatus successfully returns to normal operation mode from power saving mode.
It is a first object of the present invention to provide: an image forming apparatus that is capable of decreasing user wait time before it becomes ready for operation, by judging in an early stage if a person moves toward the image forming apparatus itself; a power control method for the image forming apparatus; and a recording medium storing a power control program for making a computer of the image forming apparatus implement the power control method.
(Second Object)
In order to judge whether or not a user has an intention to operate the image forming apparatus, the image forming apparatus needs to detect whether or not any button is pressed on its operation panel or needs to detect, with an electrostatic sensor installed on its operation panel, whether or not user's hand is close to the operation panel.
More specifically, if the image forming apparatus is capable of reducing power consumption by entering power saving mode when not in use and returning to normal operation mode when there is a user with an intention to operate the image forming apparatus itself, the image forming apparatus returns to normal operation mode only if detecting that any button is pressed on its operation panel or only if detecting, with an electrostatic sensor installed on its operation panel, that user's hand is close to the operation panel. In this case, the user possibly reaches the image forming apparatus only to find that he/she has to wait so long until it becomes ready for operation, which is very troublesome.
On the basis of the technique disclosed in Japanese Unexamined Patent Publication No. 2000-132755, an image forming apparatus has achieved in avoiding errors caused by unnecessary heat rays incoming in certain directions but still has not solved the problem mentioned above.
It is a second object of the present invention to provide: an image forming apparatus that is capable of decreasing user wait time before it becomes ready for operation, by judging in an early stage if a user has an intention to operate the image forming apparatus itself; a power control method for the image forming apparatus; and a recording medium storing a power control program for making a computer of the image forming apparatus implement the power control method.
The description herein of advantages and disadvantages of various features, embodiments, methods, and apparatus disclosed in other publications is in no way intended to limit the present invention. Indeed, certain features of the invention may be capable of overcoming certain disadvantages, while still retaining some or all of the features, embodiments, methods, and apparatus disclosed therein.